add support for {ref} placeholder

ModpackUpdater.Manager/Extensions.cs

@@ -47,4 +47,18 @@ public static class Extensions
             return @this.SourceUrl;
         return @this.SourceUrl.Replace("{version}", version.ToString(3));
     }
+
+    public static string GetInstallUrl(this ModpackConfig @this)
+    {
+        if (string.IsNullOrWhiteSpace(@this.RefTag))
+            return @this.InstallUrl;
+        return @this.InstallUrl.Replace("{ref}", @this.RefTag);
+    }
+
+    public static string GetUpdateUrl(this ModpackConfig @this)
+    {
+        if (string.IsNullOrWhiteSpace(@this.RefTag))
+            return @this.UpdateUrl;
+        return @this.UpdateUrl.Replace("{ref}", @this.RefTag);
+    }
 }

ModpackUpdater.Manager/ModpackInstaller.cs

@@ -32,13 +32,13 @@ public class ModpackInstaller(ModpackConfig updateConfig, ModpackInfo modpackInf
 
     private async Task<UpdateInfos> DownloadUpdateInfos()
     {
-        var content = await http.GetStringAsync(updateConfig.UpdateUrl);
+        var content = await http.GetStringAsync(updateConfig.GetUpdateUrl());
         return UpdateInfos.Parse(content);
     }
 
     private async Task<InstallInfos> DownloadInstallInfos()
     {
-        var content = await http.GetStringAsync(updateConfig.InstallUrl);
+        var content = await http.GetStringAsync(updateConfig.GetInstallUrl());
         return InstallInfos.Parse(content);
     }
 

ModpackUpdater/ModpackConfig.cs

@@ -13,6 +13,7 @@ public class ModpackConfig
     public string UnleashInstanceId { get; set; }
     public bool PreferDirectLinks { get; set; }
     public string MinecraftVersion { get; set; }
+    public string RefTag { get; set; }
 
     [JsonConverter(typeof(StringEnumConverter))]
     public ModLoader ModLoader { get; set; }